1. Field of the Invention
This invention relates to a clutch for a vehicle and, more particularly, to a clutch for selectively engaging an output shaft of an internal combustion engine (hereinafter referred to as "engine") with a transmission input shaft.
2. Description of the Related Art
In a vehicle employing a conventional manual transmission unit, a clutch is provided between the engine and the gearbox to control transfer of torque generated by the engine.
Such a conventional clutch system mainly consists of a dry, single friction disc, which is selectively either spaced from or in contact with an opposing, mating, member to deliver torque of the engine to the transmission unit.
As the friction disc has a high coefficient of friction, it is difficult to smoothly engage the opposing member and may produce a sudden interlocking between them.
Accordingly, a difference between the rotational speed of the engine and that of the transmission unit cannot be accommodated by such a conventional clutch mechanism.
In the interest of a smooth engagement, it is recommended that the friction disc be made of a low friction material. However, since a single low friction disc cannot deliver sufficient torque, plural discs are conventionally provided as disclosed in Japanese Patent Laid Open No. Sho 58-184321 and Hei 1-158226.
However, it is known that plural friction discs associated with the transmission unit greatly increase the inertia of the input shaft extending from the transmission unit, due to their heavy weight, and thereby impose a big load on the synchronizer system of the transmission unit, thus delaying synchronization of gears in the transmission unit.
It is an object of the present invention to provide a desirable clutch mechanism which will not impose a large load on the synchronizer system when connecting or disconnecting the output shaft of the engine in relation to the input shaft of the transmission unit, whereby the shafts can be interlocked smoothly without transmitting shock to the driver in the gear shifting operation.